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Digital QSO – True or False?

A discussion about using database information rather than radiowaves for transferring QSO information

Swedish Radio Amateur Society National convention 2012 in Umeå, Sweden

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Theory and requirements..

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Basics:

- a QSO is about transferring information via radiowaves

- a certain standard procedure is used

- callsigns, reports and acknowledgements are exchanged

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On VHF and above there are somewhat stricter requirementsfor a QSO than on HF. IARU Region 1 VHF Handbook; definition for a valid QSO on VHF and on higher bands is:

“A valid contact is one where both operators during the contact have

(1)mutually identified each other

(2) received a report, and

(3) received a confirmation of the successful identification and the reception of the report.”

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IARU Region 1 VHF Handbook says;

VALID CONTACTS:

“However no recourse should be made during the contact to obtain the required information, change of frequency, antenna direction, etc. via other methods such as the DX Cluster, talk-back on another band, etc.”

!

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The internationally adopted standard procedure for an EME-QSO says (G3SEK webpage);

“Minimum QSO: The definition of a minimum valid QSO is that both stations have copied all of the following:

1. Both callsigns from the other station,

2. Signal report from the other station

3. R from the other station, to acknowledge complete copy of 1 and 2.”

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How do we communicate via radiowaves?

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CW is King!

Analogue!

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Analogue!

Phone is.. Interesting!

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Digital is.. New!

Digital!

WSJT FSK441/JT65

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1 001 H 1202 002 I 1213 003 J 1224 010 K 1235 011 L 1306 012 M 1317 013 N 1328 020 O 1339 021 P 200. 022 Q 201, 023 R 202? 030 S 203/ 031 T 210# 032 U 211<space> 033 V 212$ 100 W 213A 101 X 220B 102 Y 221C 103 0 223D 110E 111 E 230F 112 Z 231G 113

100110001111110101000101100100011100111101101111000110101011001101010100100000011000000011010010110101010011001001000011111111

FSK441 (G4RGK SM2CEW)

JT65 (G4RGK SM2CEW)

The digitalmessage

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1 001 H 1202 002 I 1213 003 J 1224 010 K 1235 011 L 1306 012 M 1317 013 N 1328 020 O 1339 021 P 200. 022 Q 201, 023 R 202? 030 S 203/ 031 T 210# 032 U 211<space> 033 V 212$ 100 W 213A 101 X 220B 102 Y 221C 103 0 223D 110E 111 E 230F 112 Z 231G 113

100110001111110101000101100100011100111101101111000110101011001101010100100000011000000011010010110101010011001001000011111111

FSK441 (G4RGK SM2CEW)

JT65 (G4RGK SM2CEW)

Det digitalameddelandet

Transmitted character by character

Coded with symbols instead of characters

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Will this introduce any limitations?

100110001111110101000101100100011100111101101111000110101011001101010100100000011000000011010010110101010011001001000011111111

?JT65

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WSJT Manual:

Standard messages are compressed so that two callsigns and a grid locator can be transmitted with just 71 bits..

The aim of source encoding is to compress the common messages used for EME QSOs into a minimum fixed number of bits..

Yes, it creates limitations..

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Tables in the software..

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Minimal space for themessage..

SM2CEW G4RGK IO91

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Database..

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Let’s take a look at JT65..

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Who is calling….??

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Add some info in theSetup screen..

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That’s better..!?

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I’ll write another prefix..

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Wow, another DXCC….

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I’ll write something else..

Note. FUSK = ”CHEAT” in Swedish

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??….!!

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So who is really calling?

072900 9 -7 -0.3 132 5 # SM2CEW OOO 1 0 072900 9 -7 -0.3 132 5 # SM2CEW PJ4/PA3CFH OOO 1 0 072900 9 -7 -0.3 132 5 # SM2CEW 9X5/PA3CFH OOO 1 0 072900 9 -7 -0.3 132 5 # SM2CEW FUSK/PA3CFH OOO 1 0

The truth is that the software is not looking for a call.

Instead it is using a flag that says:- Write what the operator entered in the Setup screen

100110001111110101000101100100011100111101101111000110101011001101010100100000011000000011010010110101010011001001000011111111

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The ”Deep Search” concept

Or as K1JT says;

”Let’s add 4-6 dB extra sensitivity!”

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”Deep Search”

• Very weak signal levels

• Can not communicate callsigns

• Matching fragments received to database info

• Excluding unlikely matches with database info

• A qualified guesswork

• Does not write on the screen what is received but what the database says

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Dependencies:

Database

Entry fields

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Let’s try..

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Selection process, who’s not there? PA5M,JO21BS,,,ex PA5MD PA3GST,,,08/03

PA5MS,JO21QJ,EME,,ex PE1OGF,,144: 11el GS35b 400W MGF1302132 4000 DTR,11/02

PA60SHB,JO21OS,,,SpecialCall,,,12/04

PA6BN,JO13OF,,,Expedition - QSL via PA3BIY,,,07/98

PA6MS,JO32QF,,,Special-Call,,DTR,10/96

PA6T,JO32GF,,,Specialcall - QSL via PA2TAB,,DTR 3000lpm,12/98

PA7AL,JO23VG,,,,,,12/04

PA7C,JO32GF,,,ex PA2TAB,,50: 100W 6el - 144: R2CW GS31b 400W 14el MGF1,09/03

PA7FE,JO22OC,,,ex PA3BFM,,50: 6el leg pwr,03/99

PA7FM,JO21,,,ex PE1PZS,,,08/00

PA7PYR,JO21UQ,,,ex PD0PYR,,TS450SAT HF: FB33 - 144: 25W 2x17el Tonna -,09/03

PA7RP,JO22EC,EME,,ex PA3BBA,,144: 400 Watt (GS35b) 17 el F9FT,01/06

PA7WM,JO23TA,,,ex PA3DWD,,,03/99

PA9RX,JO32MT,,,,,144: FT847 4x17el 200W370,08/02

PB0ALS,JO21RV,,,,,,1993

PB1TT,JO22FF,,,ex PA3EFC,,144: 100W 10el CueDee2000lpm DTR,09/01

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The ”Deep Search” conceptFragments received, still the computer prints information as if it has been received infull. This is NOT about extra dB’s of sensitivity!

No other operator can ”see” a QSO at Deep Search level unless he sets his program up exactly like one of the two stations involvedin the QSO and makes sure the info is in thedatabase.

Without real time communication (via Internet) you don’t stand much of a chance to complete a QSO where Deep Search is in effect.

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Is ”Deep Search” the future?

No, not if we want to preserve the radio channelas the carrier of information when making a QSO!

Comparing Deep Search with traditional QSO’s is not ok when we know that the callsigns were never transferred via the radio path!

DXCC, distance records, locators, fields… all these awards based on true QSO’s are now smeared by allowing Deep Search QSO’s!

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The ”Deep Search” concept

Let me quote a ”successfull” German moonbouncer with a small EME-array consisting of two short yagis:

”the way to get a small station in the log is to set the sync negative, and switch on "Agressive decode". Then you just have to sit back and wait for the right call to pop up. After that, you can put the parameters back to default.”

Yes, he has the 2m DXCC-award his schack wall..

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Is ”Deep Search” the future?

If so, what is the next lower limit?

- shorthand calls? ” * # ”- detecting a carrier? ” – ”- a time stamp will represent a call ”120428154523 GMT” = SM2CEW

Not much different from todays Deep Search..

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SM2CEW says:

- Keep the old concept where QSO information is transferred via radio waves

- Do not compare database generated text with a real QSO

- Continue experimenting with digital protocols and digging in the noise for real information!

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CW is King!

Thanks for the attention, see you on the bands!

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